From 876e23cb2e545148a0ee4effda5c63c861855941 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Tue, 26 May 2015 19:46:32 +0100 Subject: [PATCH] linux-user: use __get_user and __put_user in cmsg conversions The target payloads in cmsg conversions may not have the alignment required by the host. Using the get_user and put_user functions is the easiest way to handle this and also do the byte-swapping we require. (Note that prior to this commit target_to_host_cmsg was incorrectly using __put_user() rather than __get_user() for the SCM_CREDENTIALS conversion, which meant it wasn't getting the benefit of the misalignment handling.) Signed-off-by: Peter Maydell Signed-off-by: Riku Voipio --- linux-user/syscall.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 15b1e81471..5cf265cb08 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -1228,17 +1228,18 @@ static inline abi_long target_to_host_cmsg(struct msghdr *msgh, int *target_fd = (int *)target_data; int i, numfds = len / sizeof(int); - for (i = 0; i < numfds; i++) - fd[i] = tswap32(target_fd[i]); + for (i = 0; i < numfds; i++) { + __get_user(fd[i], target_fd + i); + } } else if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_CREDENTIALS) { struct ucred *cred = (struct ucred *)data; struct target_ucred *target_cred = (struct target_ucred *)target_data; - __put_user(target_cred->pid, &cred->pid); - __put_user(target_cred->uid, &cred->uid); - __put_user(target_cred->gid, &cred->gid); + __get_user(cred->pid, &target_cred->pid); + __get_user(cred->uid, &target_cred->uid); + __get_user(cred->gid, &target_cred->gid); } else { gemu_log("Unsupported ancillary data: %d/%d\n", cmsg->cmsg_level, cmsg->cmsg_type); @@ -1333,8 +1334,9 @@ static inline abi_long host_to_target_cmsg(struct target_msghdr *target_msgh, int *target_fd = (int *)target_data; int i, numfds = tgt_len / sizeof(int); - for (i = 0; i < numfds; i++) - target_fd[i] = tswap32(fd[i]); + for (i = 0; i < numfds; i++) { + __put_user(fd[i], target_fd + i); + } break; } case SO_TIMESTAMP: @@ -1349,8 +1351,8 @@ static inline abi_long host_to_target_cmsg(struct target_msghdr *target_msgh, } /* copy struct timeval to target */ - target_tv->tv_sec = tswapal(tv->tv_sec); - target_tv->tv_usec = tswapal(tv->tv_usec); + __put_user(tv->tv_sec, &target_tv->tv_sec); + __put_user(tv->tv_usec, &target_tv->tv_usec); break; } case SCM_CREDENTIALS: